Dichalcogenolanes by ring-expansion of transition metal-coordinated thietanes and selenetanes
作者:Helmut Fischer、Claudia Kalbas、Josef Hofmann
DOI:10.1039/c39920001050
日期:——
Pentacarbonyltungsten-coordinated selenetanes react with seleno- and telluro-cyanate by insertion of the chalcogen atom into the Se–C bond of the selenetanes to give 1,2-diselenolanes and -selenatellurolane, respectively; the analogous reaction of (CO)5W[[graphic omitted](OEt)H] with tellurocyanate affords a 1,2-thiatellurolane complex.
Thietane and Selenetane Complexes by Thermal Cycloaddition of Vinyl Ethers to Transition‐Metal‐Coordinated Thio‐ and Selenoaldehydes – Crystal Structure of Pentacarbonyl(7‐phenyl‐2‐oxa‐8‐thiabicyclo[4.2.0]octane‐
<i>S</i>
)tungsten(0)
作者:Helmut Fischer、Claudia Kalbas、Rüdiger Sumpf
DOI:10.1002/cber.19961291005
日期:1996.10
AbstractPentacarbonyl(thiobenzaldehyde)tungsten und pentacarbonyl(selenobenzaldehyde)tungsten (1a and 1b) undergo a thermal [2 + 2] cycloaddition with several vinyl ethers to give highly substituted transition metal‐coordinated thietanes and selenetanes. The addition is highly regio‐ and stereospecific. The products undergo acid‐catalyzed rearrangements, which lead to thermodynamically more stable diastereomers of the thietanes and selenetanes. The stereochemistry of both addition and rearrangement was established by reaction of deuterium‐labeled vinyl ethers and by reaction of the cis and trans isomers of ethyl propenyl ether. The crystal structure of the bicyclic addition product of 1a and 3,4‐dihydro‐2H‐pyran is reported.